By David Crane defrev (at) gmail (dot) com July 27, 2011 DefenseReview first became aware of the TNW SGP-QCB (System Gas Piston-Quick Change Barrel) 5.56x45mm NATO (5.56mm NATO)/.223 Rem. gas piston/op-rod tactical AR carbine/SBR (Short Barreled Rifle) weapons/upper receiver assemblies in December 2009 in a NorthwestFirearms.com forum thread. We subsequently did some additional research on the system in early June …

By David Crane defrev (at) gmail (dot) com April 21, 2011 Updated on 4/21/11. A company called Adcor Defense is manufacturing and marketing a new gas piston/op-rod (operating rod) tactical AR (AR-15) rifle/carbine/SBR (Short Barreled Rifle) called the B.E.A.R. Gas Piston Rifle (GPR). “B.E.A.R.” is an acronym that stands for “Brown Enhanced Automatic Rifle”, since the weapon was designed and …